<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    #d1{
      width: 100px; height: 100px;
      border: 1px solid red;
      /*margin-left: 100px;*/
      /*margin-top: 50px;*/
        /*四个方向同时设置外边距*/
        /*margin: 50px;*/
        /*同时设置上下和左右的外边距*/
        /*margin: 100px 50px;*/
        /*分别设置上右下左的外边距*/
        margin: 10px 20px 30px 40px;
    }
    #d2{
        width: 100px; height: 100px;
        border: 1px solid red;
        /*上下相邻两个元素彼此添加外边距，取最大值*/
        margin-top: 50px;
    }
    #s1{
        /*行内元素上下外边距是无效的*/
        margin-left: 50px;
    }
    #s2{
        /*左右相邻彼此添加外边距，两者相加*/
        margin-left: 30px;
    }
    #big{
        width: 200px; height: 200px;
        background-color: green;
        /*解决粘连问题*/
        overflow: hidden;
    }
    #big>div{
        width: 50px; height: 50px;
        background-color: blue;
        margin-left: 50px;
        /*当元素的上边缘和上级的上边缘重叠时，给元素添加外边距会出现粘连问题
        给上级元素添加overflow: hidden解决*/
        margin-top: 50px;
    }
  </style>
</head>
<body>
<div id="big"><div></div></div>
<span id="s1">span1</span>
<span id="s2">span2</span>
<div id="d2"></div>
<div id="d1"></div>
</body>
</html>